This invention relates generally to isolation fasteners used to acoustically isolate items from sources of vibrations, and more particularly to such fasteners used for acoustically isolating wallboard panels from adjacent sound sources, such as nearby living spaces.
A significant issue in housing construction and in multi-family housing construction in particular, is the acoustical isolation between rooms and living units both horizontally and vertically adjacent. Currently, a variety of resilient channels and other sorts of isolation clips are used with varying degrees of cost and effectiveness. It is known to provide a resilient, formed metal channel fastened to a frame member such as wall supports (studs) or floor joists, and to then secure wallboard panels to the channel to isolate the wallboard from the underlying supports. In this scenario, sound transmission through the supports or joists is disrupted, and the space enclosed by the wallboard is somewhat insulated from outside noise. One source of such channels is CEMCO, City of Industry, Ca. with the channel sold as RC-1 Resilient Channel. However, in some applications, the use of RC-1 type resilient channel has not provided the desired level of acoustical isolation.
It is also known to provide a clip for use in suspending the RC-1 channel from the underlying supports or joists. More specifically, an RSIC sound isolation clip is produced by PAC International, Inc. (www.pac-intl.com). RSIC clips include a metal bracket provided with a cylindrical resilient pad with a plurality of integral resilient standoffs for engaging the frame member, typically a floor joist or a vertical wall stud. Opposite the pad, the bracket is connected to each leg of a generally “U”-shaped or “hat” channel which defines a space between the pad and the wallboard panel which is secured to the channel. The pad provides the acoustical isolation between the frame member and the wallboard panel.
One drawback of these clips is their relatively high cost, which can approach several dollars each. In addition, the RSIC clip system described above involves a relatively rigid attachment system of the wallboard panel to the frame member. Under the general principles of sound transmission, such rigid attachment generally correlates to a more efficient transmission of sound energy. Thus, such known clip systems are relatively costly for the amount of sound isolation provided.
Sound rated floors are typically evaluated by ASTM Standard #E492 and are rated as to Impact Insulation Class (IIC). The greater the IIC rating, the less impact noise will be transmitted to the area below in the case of floors. Floors may also be rated as to Sound Transmission Class (STC) per ASTM E90. The greater the STC rating, the less airborne sound will be transmitted to the area below. Desired IIC ratings for such wallboard systems are at least 50 and most preferably approaching 60.
Another factor in conventional sound insulation systems is the amount of instruction required for proper installation. Conventional clip systems are relatively complicated and when improperly installed, the desired levels of sound insulation are not achieved.
Thus, there is a need for an improved system for reducing acoustical transmission of wallboard panels, preferably exceeding the IIC rating of currently available systems. There is also a need for such an improved system which is compatible with conventional channels such as resilient channels. There is also a need for an improved clip for such a system which is relatively inexpensive and relatively easy to install.